The combined inductance of two coils connected in series L = L1 + L2 + 2M In series adding case L1 + L2 + 2M = 0.6 H ——–(1) In series opposing case L1 + L2 − 2M = 0.1 H ——–(2) Subtracting eqn (2) from eqn (1) we get 4M = 0.5 H M = 0.125 H Let L1 = 0.2 H (since the coil when isolated, its self-inductance is 0.2 H) Putting the value of M & L1 in equation (2) 0.2 + L2 + 2 ×0.125 = 0.06 0.2 + L2 = 0.35 L2 = 0.15 H
When the field winding is connected in series with the armature winding while supplying the load then the generator is called a series generator. Current Relations As all armature, field, and load are in series they carry the same current. IL = Ise = Ia
The amount of flux produced by the magnet indicates the strength of the magnet. The more the magnetizing force (MMF), the more is the flux produced. The more the opposition to the flux path (i.e., reluctance or magnetic resistance) less is the flux produced. This relationship is expressed as Flux = MMF/ Reluctance Reluctance is the opposition offered by the material in the flux path to the establishment of the flux. The reluctance in a magnetic circuit is similar to the resistance in an electric circuit. Reluctance is the inverse of permeance. MMF = Flux/Permeance
While estimating the overhead lines, the first and last pole is always earth connected and after every 3rd electrical pole, the fourth pole is earthed. Therefore, the approximate number of required ground set = 4
EXAMIANS